1. Field of Invention
The present invention relates to a selective one-way wrench and, more particularly, to a selective one-way wrench with a device for retaining a socket.
2. Related Prior Art
A selective one-way wrench is a hand tool with which a user can select from two directions of driving a socket in order to tighten or loosen a nut or screw. In use, as it can be pivoted in an opposite direction without driving the socket, saved are the troubles in disengaging the socket from the nut or bolt and engaging the socket with the nut or bolt repeatedly. Hence, it is popular. The socket is inserted in a selective one-way mechanism of the selective one-way wrench. The polygonal periphery of the socket is fit in a polygonal hole of the selective one-way mechanism. The selective one-way wrench is often used in a horizontal surface. Hence, a user often has to hold the selective one-way wrench with a hand and the socket with the other hand in order to prevent the socket from dropping.
In order to solve the problems related to the retaining of the socket, most selective one-way wrenches include a detent biased by means of a spring. The recovering force of the spring is used for retaining and disengaging. If the elastic coefficient of the spring is too small, the retaining is not effective. If the elastic coefficient of the spring is too large, it requires a strong pushing force to insert the socket and a strong pulling force to disengage the socket. The operation demands a lot of labor and is inconvenient. Moreover, after some time of use, the detent and the socket soon wears, thus compromising its lifecycle.
In order to eliminate the above-addressed problems, the inventor of the present invention has devised a selective one-way wrench with a device 70 for retaining a socket 60 as shown in FIG. 8. The retaining device 70 includes a pushing strip 71 on a side of a handle 50 facing a selective one-way mechanism 55. A spring 72 is compressed between the pushing strip 71 and the handle 50. The pushing strip 71 will be returned after it is moved and released. The pushing strip 71 includes, at an end, a detaining strip 75 inserted into an opening of the selective one-way mechanism 55. The retaining strip 75 can be inserted in and moved from a groove 65 in the periphery of the socket 60. By pushing forwards the pushing strip 71, a user moves the retaining strip 75 from the groove 65 of the socket 60 so that the socket 60 can be disengaged from the selective one-way mechanism 55. On the contrary, as the pushing strip 71 is released and returned, the retaining strip 75 is inserted into the groove 65 of the socket 60. As mentioned above, the operation is convenient and saves labor.
The retaining device 70 performs better than the spring-biased detents. However, after further studies, it has been found that the use is not perfectly smooth as the pushing strip 71 is installed on one side of the handle 50. Moreover, it is inconvenient for the user to move his or her thumb from the selective one-way mechanism 55 to the pushing strip 71 as the pushing strip 71 is installed on one side of the selective one-way mechanism 55. Hence, there is room for improvement.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.